Like similar apps, this one will crop existing photos and rotate photos by increments of 90 degrees. It does not appear to be able to straighten existing photos by less than 90 degrees; I tried, to no avail. This app implies it will straighten a) existing photos, and b) new photos through the app. It doesn’t do “a”, unsure if it does “b”, didn’t try that yet. This app is not what I wanted, but I paid for it so I may try to use it, someday. I already have a similar app. I wanted to straighten existing photos by 15 degrees or less, not rotate them by 90 degree increments. Note: Just found that iOS has a free built-in existing Photo Edit straightener.